1. Field of the Invention
The present invention relates to an optical device, and more particularly, to an optical device having an optical waveguide including an organic Bragg grating sheet.
2. Description of the Related Art
In general, various conventional technologies have been used to manufacture an organic Bragg grating for an optical device. The various conventional technologies include replication, molding, embossing, stamping, e-beam writing, lithography, photochemical processing, and the like. The first six technologies are commonly used to manufacture surface relief gratings, and the photochemical processing is used to manufacture surface relief gratings or volume index gratings.
A representative example of an organic surface relief grating and application thereof includes a polymeric wavelength filter with a polymer Bragg grating for an optical waveguide, which is manufactured by integrating high-refractive-index resol gratings on a core layer of a low-loss polymer optical waveguide (Min-Cheol Oh et al., Polymeric wavelength filters with polymer grating, Applied Physics Letters, Vol. 72 No. 13, 1559 (1998)). Besides, a tunable wavelength filter is produced using a thermal electrode and a thermo-optic effect (Min-Cheol Oh et al., Tunable wavelength filters with Bragg Gratings in polymer waveguides, Applied Physics Letter, Vol. 73 No. 18, 2543 (1998)). The high-refractive-index resol gratings are manufactured by a phase mask and photolithography.
For a representative example of organic volume index gratings and application thereof, a Bragg-grating writing process is performed on a planar polymer optical waveguide using two-beam interference and corresponding photolocking of an allied signal optical polymer, and the resulting product is applied to an optical device such as a multi-channel optical add/drop multiplexer (OADM) (Louay Eldada et al., Integrated Multichannel OADMs Using Polymer Bragg Gratings MZls, IEEE Photonics Technology Letters, Vol. 10 No. 10, 1416 (1998), Louay Eldada et al., Thermooptic Planar Polymer Bragg Grating OADMs with Broad Tuning Ranage, IEEE Photonics Technology Letters, Vol 11 No. 4, 448 (1999)).